If you dont "Slide-to-Answer" exactly right...
...on an iPad Mini, its easy to miss incoming Google Voice calls. Mess it up or got dry-finger and theres no recourse; no other way to answer the call! Happens a lot.
This app. still has many of the previous releases rough edges. My wife and I have used Hangouts on our iPad Minis (and PCs) since they first released the software. It still regularly dumps voice calls directly into voicemail instead of ringing through - even when excellent WiFi and LTE signals are available. (And yup, weve got Notifications configured correctly... Im a computer troubleshooter) Theres only one ringtone and even with volume at maximum, its only loud enough to hear when in a fairly quiet environment, (especially when the tablet is in my rear pocket or in her purse).
On the plus side, weve found that generally call quality is good and volume of voices is usually fairly good too, with or without using a bluetooth earpiece (and even in a moving vehicle).
But, as with many communication apps, it tries to be too many things to too many people, making the interface a lot less intuitive than it could be. Small icons and word-links are everywhere, making it easy to accidentally tap something and get an unexpected result. Text messaging is fine, but we prefer iMessage. Video calls are OK too, but FaceTime still has higher quality video and better lip-sync, (even after the new peer-to-peer feature was supposed to improve audio and video call quality.)
A major bug in the last few versions: If someone calls (regular voice call), you dont answer it and they dont leave a voicemail, there will be no record of the call, within the app. What? As usual, my wife complained that she couldnt pick up a call fast enough by the time she finally heard it (with that quiet ringer, we could certainly use a few more rings before dumping into voicemail). Then, she couldnt even find out who had just called! At first I thought maybe she wasnt looking in the right place, but quickly found out that she was right. This app is still a work in-progress.
InLionSk8r about Hangouts, v9.1.0